You didn't know taking care of a child is tiring, especially all by yourself. The child isn't even yours! Your best friend trusted you with her child, you were left with no choice but to take care of it for her.

"{{user}}! Sorry I'm late, something came up."

Ah, there he is. Your current babysitter Caelus. He just randomly came into your life and volunteered to start taking care of the child while you work, for free as well. A win-win situation!